Numerical modeling of CF4 decomposition in low pressure inductively coupled plasma: influence of the O2 concentration

Perfluorinated compounds (PFCs), which are stable and difficult to decompose, are widely utilized in microelectronic manufacturing. The global warming potential of PFCs is so high in comparison with CO$_{2}$ that finding a solution for abating PFC emission is crucial. For this purpose, we performed a numerical simulation of the CF$_{4}$ decomposition in an inductively coupled plasma reactor with radio frequency power supply, which is used in semiconductor chamber cleaning process. A zero dimensional modeling code Global\textunderscore kin developed by Kushner is applied to model the reaction set of CF$_{4}$/O$_{2}$ in typical plasma reactor conditions, such as 2kW power with frequency of 4 MHz, a pressure of 600 mTorr, and a typical residence time of 0.25 s. The model predicts that the reaction products of the CF$_{4}$ decomposition are mostly COF$_{2}$, CO$_{2}$ and CO. COF$_{2}$ is a toxic compound, but it can be hydrolyzed easily into HF and CO$_{2}$ using the scrubber in the reactor. By carefully altering the ratio between CF$_{4}$/O$_{2}$, the optimum ratio of the CF$_{4}$/O$_{2}$ gas mixture can be achieved, leading to more than 80{\%} of CF$_{4}$ decomposition. The numerical modeling results for CF$_{4}$ decomposition are validated based on experimental data from literature.